Protective device for signal systems.



v No. 839,365. PATENTED DEC. 25, 1906.

v F. B. COREY PROTECTIVE DEVICE FOR SIGNAL SYSTEMS.

, APPLICATION LBD AUG. 1-, 1904..

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Witnesses- Invent Fred B. Cove-g.

' To allwhomit may concern:

U TE ST T S, PATENT OFFICE.

FRED B. COREY, OF SCHENECYIADYQNEW YORK, Assicnon TO GENERAL ELECTRIC COMPANY, A CORPORATIQNOF NEW YORK.

PROTECTIVE DEVICE FOR SIGNAL-SYSTEMS.

Specification of Letters P atent;

rammed ec. 25, 1906.

Application filed August 1,1904. Serial No. 219,073.

' Be it knownthat I, FRED B. OoE'EY, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Protective Devices for Signal Systems, of which the following is a specification.

- My invention relates to block-signal systems for electrically-operated railways and v its object is to protect therelays and other apparatus connected to therails from injury by the power-current.

system it is customary to sectionalize one of the rails for the purposes of the block-signal system and to leave't e otherrails continuous to serve as a part 0 the return for the direct-current power-circuits If defective.- bonding GXISlJS on the continuous ra1l,'1t 1s evident that a considerable potential may arise between the continuous and sectional rail when a train bridges the defective bond. With the train in this position current would tend to flow from the'continuous rail through the axles at one end of the train to the sectional rail and-thence back throu h the axles at the other end of the train to t e continuous rail.

Since the signal devices including the track-relays and sourceof current there-- for are adapted for low voltages only, a

suflicient potential'may be produced by the flow of power-current to .damage'or destroy the relay-winding or source of current. By my invention I- employ anv electromagnetic overload. device connected in series or in parallel withthe relay or source of current, or 0th, and arranged to short-circuit the signal device whenever an abnormal potential occurs between, the rails, so that the current through the signal device can never rise to a dangerous amount.

My invention will best be understood by reference to the accompanying drawing,

which shows"diagrammat1cally one block of of a .railway with the signal system arranged I in accordance with my invention.

' I have shown my invention as applied to an alternating-current-signal system, since alternating current has'acertain advanta es operated rai Ways, both because the alter,- nating current may be readil transmitted along the line, thussaving t. e expense of In electrically-op erated railways employing a block-signal 4 other manner w'hi'c' batteries, and because alternating-current apparatus is not liable to be affected b leak age-currents from the rail-circuit. t will be understood, however, that my invention is equally applicable to block-signal systems operated by direct current.

In the drawing, T represents a transformer havin' its primary connected to" the lines L L, which convey the alternating current for energizing the signal system. The

- secondary of the transformer is connectedto the rails, of which the rail R is represented as, continuous-and the rail R as sectionalized. A magnet-winding M'is connected in series,-

-Wll'/h' the secondary of transformer T and controls a switch-contact S, whichwhen magnet M is energized with a certain strength is drawn up and short-circuits the. secondary of transformerT; By properly proportioning the magnet-winding-M 1t is evident that the secondary of the transformer T may be short-circuited u on the occurrenceof an" abnormal potentlal at the rails, and consequently protected. from an excessive flow of power-current. The transformer T'is shownas of the open-core type, so that an excessive short-circuit current is prevented.

W represents a relay of the wattmetertylip,

' having its movable winding connected to other end of the block and its stationary winding energized from a second transformer T. The movable winding of this relay is protected by means of aosecond magnetwindingM and switch-contact S" controlled thereby. P represents the sema here-post, on which is a si al which may e controlled-bythe re v The connections between the relay and the nal are not shown, since they form no part of my present invention and since man operative connections between'relays an signal-arms are well known' in the art. v I It is evident that instead ofbeing connected in series-with the relays themagnetwindings M M me be connected in any sponsive tothe occurrence of an abnormal potential on the rails, producin an excess-. ive flow of current through the evice to be protected, and the actiolnwill be the same in either case. v I have 'shown protective devices. applied both .to the track-rela'v and to the source of will render them re-- current therefor, and I desire it to be undersaid rails.

- sai stood that the term signal device in the appended claims is intended to include any low-voltage device pertaining to the signal system and connected to the track-rails.

,What I claim as new, and desire tosecure by Ijetters Patent of the United States, is

1. In a block-signal system for electrically operated railways, a signal device connected to,

to the rails, andan overload relay adapted and arranged to short-circuit said device upon an abnormalrise of potential between 2; In a block-signal system for electrically; operated railways, a signal device connected 'to the rails, a magnet-Windingin series with said device, anda switch controlled by said Ina net-winding and adapted to short-circuit device, v

3. In a block-signal system for electricallyoperated railways in which the rails serve as return conductor'for the power-current, a signal device connected .tothe rails,-and an electromagnetically-operated switch arranged to close a shunt-circuit around said device upon an excessive. flow of power-current through said. device. e i a 4. Ina block-signal system for electricallyoperated railways in which the rails serve'as return conductor for the power-current, signal devices connected to the rails at opposite j ends of the block, and an electron'iagnetic-v ally-operated switch for each device arranged to close 'a'shunt-ciI'cu-it around said device upon an excesslve flow of power-currenttherethrough'.

5. In'a block-signal system for electricallyoperated railways in which the rails serve as return-conductor for the power-current, a transformer having its secondary connected to the rails, a resistance inserted between said secondary and the rails, and an electromagnetically-operated switch arranged to close a shunt-circuit across the rails between the rails and said resistance upon an excess ive flow of power-current through the transformenseconda'ry.

6. In a block-signal system for electricallyoperated roads in which the rails serve as returnconductor for the power-current, a transformer, leads from the secondary of the transformerto the rails, a resistance inserted in said leads, and an electromagnetically-operated switch arranged to short-circuit said leads between the resistance and the rails upon an excessive flow of power-current in FRED B. COREY.

Witnesses:

uBENJAMIN B. HULL,

HELEN ORFORD. 

